President Barack Obama once held such a dominant lead among women that top conservatives warned Mitt Romney not to waste much time targeting them.
Then came the Denver debate.
The president's sudden slide among women after that revealed just how fluid their support truly was — and it's forced Obama and his Democratic allies to spend the final days of the campaign fortifying what had appeared to be an indestructible female firewall.
To win reelection, Obama needs big margins among women. But a spate of national polls, and even some battleground state surveys, shows his robust leads have slipped away. The challenges after the first debate have remained for Obama as Romney continues to reshape his candidacy with a more moderate message on foreign policy, abortion and taxes.